Fuse construction



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Patented Feb. 11, 1941 UNITED STATES PATENT OFFICE FUSE CONSTRUCTION Application August 12, 1937, Serial No: 158,652 9 Claims. (01. zoo-.114

This invention relates to a fuse construction. Objects of this invention are to provide a very simple type of fuse construction which may be used in any capacity but is eminently suitable for use as a secondary fuse.

' It is well known that where very small amperage primary link fuses are used when fusing a transformer, that it is usually the practice to use nothing smaller than a 3-ampere fuse for ex,-

1'0 ample, with the result that there is often over fusing of the smaller transformers, particularly of the 13,000 volt class, and secondaryfuses are therefore necessary for overload protection."

Additionally, it is advisable to use secondary 15 fuses where there are grouped secondaries of the transformers to prevent outage of the entire group in case of failure of a single transformer.

This invention is designed to provide a fuse which may be of the suspension type or which 2 may be supported by brackets from any suitable support, which may be employed directly in the secondary line, which maybe mounted either horizontally or vertically, or in an angular position.

25 In general this invention is an improvement over that disclosed in the copending application of Alwin G. Steinmayer Serial No. 52,792 filed 1 December 4, 1935, for Fuse construction, which since the filing of the present application has 30 matured into Patent No. 2,113,632 on April 12,

This invention has for a further object the provision ofa fuse construction in which an ordinary type of insulating strain member serves as a spac- 35 ing member for the terminals and as a supporting member for the fuse assembly, and in which the strain member, which may be an ordinary suspension typeinsulator, may be formed of porcelain and may provide, as stated, the body portion of 40 the device, the construction being such that the line wires themselves may be employed to supportthe device or the device may receive the line wires either directly at the terminals or may receive the line wires by having the line wires 45 formed in loops with the loop of one line interlinking with the loopof the other line wire, thus placlng theporcelain member under compressionwith, however, the fuse assembly spaced outward.- ly from the body portion.

v 50 Further objects are to provide a fuse construction of the type hereinabove referred to in which a fuse assembly, which may include a fuse tube and a fuse link, is movably supported from the body portion, preferably being pivotally supported 55 from one of the terminal members, in which the shown in Figure 1.

other terminal member forms a latch portion for the free end of the fuse assembly, and in which mechanism controlled by the fuse link is provided which is released when the fuse link is ruptured, thus allowing the fuse tube to drop to inoperative position with the-freely movable end of the fuse tube mechanically moved away from the corresponding terminal of the body portion.

Further objects are to provide a fuse construction which may be either of the suspension type or may be carried by a bracket from a support, which is so made that it may be worked hot, that is to say, which may be refused and either partially closed or wholly closed by a switch stick to thus allow the operator to stay out of the danger zone, the construction allowing the lineman to feel out the circuit to see if theexcessive load, from short circuit for instance, is still on. For example he may momentarily push the fuse against the contact and if a short circuit still exists, the fuse will blow, but he is far enough away to avoid possible injury. After he has felt out the circuit, he can slam the fuse tube home in its contacts Again, if it becomes desirable or necessary to. open the circuit, the lineman can pull the fuse tube to open position by means of a switch stick without damagingthe fuse link. Also, in refusing, he may remove the fuse tube from the body portion during refusing and may freely handle the fuse tube and its associated parts, as he is not required to manipulate any fuse link, thumb nut or other parts of the fuse tube assembly while the device is alive.

Further objects are to provide a construction having the characteristics hereinabove outlined which is of the drop-out type, arid in which a relatively short.fuse tube may be employed, but which nevertheless when the fuse tube has dropped to inoperative or drop-out position, provides a long leakage path. I

Further'objects are to provide a construction which has a relatively small number of simple, easily produced parts and which are economical to manufacture, and in which a conventional type of strain insulator may be employed for the body portion of the device.

Embodiments of the invention are shown in the accompanying drawings, in which: v

Figure 1 is a side elevation, partly in section andwith parts broken away, showing one form '50 that the invention may-take and showing the manner in which the device may be attachedto a cross-arm or other support. Figure 2 is an end elevation of the structure Figure 3 is an enlarged sectional view through the fuse tube showing a portion of one of the terminals.

Figure 4 is a side elevation of a further form 5 that the invention may take.

Figure 5 is a sectional view on the line 55 of Figure 4.

Figure 6 is a view corresponding to Figure 1 showing a. further form of the invention.

10 Figure 7 is a view corresponding to Figure 1 showing the manner in which the line wires may be dead ended on the device while the device is supported from a suitable support.

Referring to the drawings, particularly Figure 1, it will be seen that thedevice comprises the ordinary type of strain insulator indicated, at I which is provided with grooves 2 and with diametrically arranged spaced apertures 3 so that when desired the conductors may be interlooped and may lie within the grooves 2 and pass through the apertures 3 in a well known manner as shown in Figure 7, to thus place the intermediate portion of the insulator under compression and to also form a very secure mechanical attachment for the conductors.

In the form shown, the line wires 4 lead directly to the terminal members 5 and may be secured thereto by the connectors 8 or in any suitable manner. The terminal members 5 may consist of strap metal whichis secured to the end faces of the insulating body portion 1 by means of the screws 7 and the nuts 8. One of the terminal members 5 may have a lower portion 8 shaped into an open eyelet for receiving the toggle link mechanism hereinafter described. The

other terminal member 5 may extend downwardly and may have achannel lower portion l8 with a slightly shouldered portion II to form a spring latch or terminal latch for the end of the fuse tube assembly. A reinforcing strip I! may be employed to back up the spring latch or terminal latch l0 if desired, as shown particularly in Figural.

The fuse assembly may comprise an insulating fuse tube l3 open at both ends and it may have one of its ends internally flared, as indicated at l4, to assist in the discharge of gases. This fuse tube carries a fuse link, indicated generally by the reference character I5, which may take the form disclosed in the copending application of Ralph H. Earle Serial No. 83,498 filed June 4, 1936, for Fuse link construction, which since the filing of the present application has matured into Patent No. 2,104,899 on January 11, 1938, or which may take other forms.

As shown in Figure 3, one form of fuse link may have an outer flat portion l8 which terminates in a head I! and a metallic washer I 8, which together close the end of the fuse tube I3.

60 The fusible portion may consist of overlapping parts [9 located within a small insulating tube 28 and independently tensioned by a sm'all helical spring 2| which fits loosely over a small copper tube 22 to which one end of the fusible link is secured. At one end the spring 2| is securedto a collar 23 bearing against the outer end of the small insulating sleeve or tube, 28 and at its other end the spring bears against a porcelain, glass, or other insulating sleeve 24 surrounding the fuse 0 link and bearing against the copper tube 22, thus placing the fuse link' under tension. The outer end of the copper tube 22, to which the fuse link is secured; is itself secured to a flexible leader 25. The details of this particular portion of the construction are set forth with greater particularity in the copending application of Ralph H. Earle hereinabove mentioned.

The toggle link mechanism comprises a lever 28 which has a pivot portion 21 provided with a flat face. and positioned within the supporting eye 8 of one of the terminals. This lever 28 extends part way across the outer end of the fuse tube i3 and is provided with an angularly formed portion 28 which carries the screw 29 and thumb nut 38 by means of which the leader 25 of the 10 fuse link is secured. This leader is led over the shouldered portion SI of the lever 28, see Figure 2, and thus serves to retain the lever in position and to hold one face of the portion 28 thereof in contact with the fuse tube, as shown in such fig- 15 ure. This lever 28 is pivoted at an intermediate point to the ears 32 of a fitting 33 into which the fuse tube is screwed, as shown most clearly in Figure 1.

It is apparent, therefore that when the fuse 20 link is intact, it holds the parts in the position shown in Figure 1. The head of the fuse link is directly engaged by the spring latch terminal portion HI and is located above the shoulder H. Preferably a small tongue 34 is struck outwardly 25 from the portion i 0 to form an upper stop for the fuse tube so that the lineman may freely push the fuse tube into place, rocking it about the pivot 21, with the assurance that the tube will be arrested in its closing motion inthe proper 30 position. I

The operation of the apparatus is as follows:

If an overload occurs and the fuse link is ruptured, .the toggle link mechanism, consisting of the levers 28 and 32, the ears 32 themselves con 35 stituting levers, will be released and the fuse tube will then drop downwardly to inoperative position, thus moving the free end of the fuse tube to a point considerably spaced from and out of conv I tact with the spring latch terminal i I. 40

M It is apparent also that the tension on the fuse link is slightly supplemented by the spring pressure of the relatively springy terminal II which tends to ,force the tube to the left as viewed in Figure 1 and thus transmits tension to the fuse 45 link. The fuse link also is inherently tensioned by the peculiar construction thereof as outlined in detail in connection with Figure 3.

It is apparent. that the device can be used as a suspension type drop-out fuse in which event, the conductors'would support the device as shown in Figure 6 and as described hereinafter.

If desired, the device may be supported from a cross-arm or other support 35 by any suitable type of bracket. For instance, the Z-type 55 bracket 38 may be employed and may be provided with a prong 31 at its outer end to prevent turning when the bracket is secured by means of the bolt' 38 to the under face of the cross-arm. The insulator l is provided with an aperture 00 therethrough through which a bolt 33 may be passed to attach the lower arm of the Z-shaped bracket to the insulator or body portion. Also this bracket mayfhave a small finger 48 at its lower outer end which may be received in a re- 85 cess formed in the insulator to thus prevent turning of the insulator on the bracket. 7

It is obviously possible to use many other forms of brackets or other forms of supports for the device. If desired, a U-shaped supporting -7 bracket may be employed as indicated by the reference character 4| and may have its opposite arm secured to the insulator l by the bolt 42, such bolt corresponding to the bolt 38 previously described. The bracket 4| may be attached to 76 any suitable support and if desired a reinforcing apertured portion 43, see Figure5, may be provided.

It is obvious that many other forms of bracket or supporting means may be provided without departing from the spirit of this invention.

It is also obvious that if desired the conductors may be dead ended on the device itself, as shown in Figure '7, although the device is supported by a bracket or other suitable support. The construction of Figure 7 may be like that shown in Figure l and has been so illustrated in the drawings, or may be like that shown in Figure 6. In other words, the fuse tube may have a closure cap as shown in Figure 6 or may be without the closure cap as shown in Figure 1. The dead ended conductors in Figure 'l are indicated by the reference character 4.

In Figure 6 a further form of the invention has been shown and in this form the entire structure may be carried from a bracket, as previously described, or may be suspended directly from the conductors, as has-been shown in Figure 6. The insulator is indicated, by the reference character 44 and is provided with. apertures 45 through which the interlooped conductors 46 and 41 are passed, the conductors being tied or twisted upon themselves and passing to the terminals 48 and 49 respectively and being connected thereto in any suitable manner, as by means of the connectors illustrated.

The terminal member 49 extends downwardly and is provided with an open hook or loop 50 .which pivotally receives the pivot portion 5! of the toggle link mechanism formed of the parts 52 and 53, as previously described, the member 52 having the threaded stud 54 and the thumb nut 55 for clamping the leader 56 of the fuse link, such fuse link having the usual reduced portion 51 and the button head 58.

The fuse tube 59 is carried by the member 53 of the toggle link mechanism into which it may be screwed or'otherwisefastenedn as shown in Figure 1,. for instance, and is open at the end carried by the member 53. The other end of the insulating fuse tube is provided with a contact which may comprise the metal fitting 60 screwed on the end of the tube 59 and having a reduced externally threaded end for the reception of the contact cap ii. The button head of the fuse link is clamped between the members 60 and GI in the usual maner.

The'terminal member 48 extends downwardly and, as described in connection with Figure 1, a

is provided with a channeled contact portion 62 provided with 'a small shoulder 63 adapted to seat beneath the cap Iii when the fuse is in its closed or operative position. The upward motion of the fuse tube during closing is limited by means of a small tongue 64 struck out from the contact member 62. Preferably a reinforcing or stiffening spring 65 is provided and assists the member 62 to insure adequate contact pressure between the cap GI and the member 62.

As previously described, the terminal members ll and 49 are secured directly to the outer ends or faces of the insulator H.

The operation of this form of the invention is the same as that described in connectionwith Figure 1. The rupturing of the fuse link releases the toggle mechanism and allows the fuse tube to move to inoperative position as previously described. It is to be noted, however, that in this form of the invention a contact is provided spirit of this invention.

' upon rupture of said fuse link. said fuse It will be seen that a device constructed in accordance with this invention is very serviceable. A lineman, when the fuse has blown, may completely remove the fuse tube assembly from the body portion and may refuse it. When this refusing has been done, the fuse tube assembly may be re-positioned in thepivotal support furnished by one of the terminal members as hereinabove described and the lineman may, by means of a switch stick, push the fuse tube assembly upwardly into momentary contact with the spring latching contact to thus feel out the line. Obviously if the overload still exists, the fuse will blow but the lineman is out of the danger zone. On the other hand, if he finds the circuit normal, he may then push the tube home.

Again, if it is desired to use either form of the device as a switch to. open the circuit, as for example when work is being done thereon, the lineman can pull the fuse tube toopen position with a switch stick without breaking the fuse link.

' Additionally, it will be seen that the invention provides a very simple construction that consists of a small number of easily produced inexpensive parts. Also it is to be noted particularly that a standard type of insulator can be employed for the body portion, thus materially reducing the cost of manufacture.

While the devices have been shown as supported in a horizontal position, it is obvious that they may be supported in a vertical position or in other positions without departing from the Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

' Iclaim: i

1. A suspension fuse construction comprising a body portion formed of insulating material and having means for receiving conductors to support said body portion and having terminal members electrically connected to said conductors, and a fuse assembly including a fuse tube, releasable mechanism supported from one of said terminal members, and a fuse link controlling said mechanism and normally electrically connecting said terminal members, said fuse link being a distinct and separate member from said releasable mechanism, said mechanism releasing said fuse assembly for drop-out motion upon rupture of said fuse link, said fuse link having a head at one end bearing against the end of said tube and normally engaging the other of said terminal members.

2. A suspension fuse construction comprising a body portion formed of insulating material and having means for receiving conductors to support said body portion and having terminal members electrically connected to said conductors, and a fuse assembly including a fuse tube, releasable mechanism supported from one of said terminal members, and a fuse link controlling said mechanism and normally electrically connecting said terminal members, said mechanism releasing said fuse assembly for drop-out ,mogon necting said terminal members, said fuse link being a distinct and separate member from said releasable mechanism, said mechanism releasing said fuse assembly for drop-out motion upon rupture of said fuse link, said fuse link having a head at one end bearing against the end of said tube and normally engaging the other of said terminal members, one of said terminal members being resilient and tensioning said fuse link.

4. A drop-out fuse construction comprising a body portion formed of insulating material, terminal members secured to the ends of the body portion and projecting from said-body portion, a fuse assembly including a fuse tube having a contact at one end only and having link mechanism adjacent such end for normallyholdingsaid fuse assembly in operative position, said fuse assembly including a fuse link extending through said fuse tube and restraining said link mechanism against releasing motion, said fuse link be- I ing a separate and distinct member from said link mechanism, said fuse link normally electrically connecting said terminal members, and said link mechanism when released upon rupture of said fuse link releasing said fuse tube for pivotal motion at that end thereof adjacent said link mechanism, whereby said fuse tube moves from operative to inoperative positon, said fuse tube normally substantially paralleling said body portion.

5. A drop-out fuse construction comprising a body portion formed of insulating material, said body pout-ion having apertures therethrough for the reception of interlooped conductors, terminal members secured to the ends of the body portion and projecting from said body portion and electrical-ly connected to said conductors, a fuse assembly including a fuse :tube having a contact at one and only and having link mechanism adjacent such end for normally holding said fuse assembly in operaitive position, said fuse assembly including a fuse link extending through said fuse tube and restraining said link mechanism against releasing motion, said fuse link normally electrically connecting said terminal members, and said link mechanism when released upon rupture of said fuse link releasing said fuse tube for pivotal motion at that end thereof adjacent said link mechanism, whereby said fuse tube moves to inoperative position, said fuse' from operative tube normally substantially paralleling said body portion.

6. A drop-out fuse construction comprising an insulator forming a body portion, terminal members projecting from the ends of said body portion, supporting means, a bolt intermediate the ends of said body portion for attaching said body portion to said supporting means. and adropout fuse assembly located below said body portion and including an insulating fuse tube and a fuse link enclosed by said fuse tube and normally electrically connecting said terminal members.

7. A drop-out fuse construction comprising an insulaltor'forming a body portion, said body portion having means to which conductors may be anchored, a supporting bracket for supporting said body portion, terminal members carried by said body portion and electrically connected to said conductors, and a drop-out fuse assembly normally electrically connected to said terminal members and including an insulating fuse tube enclosing a fuse link, said drop-cu t fuse assembly being located below said body portion.

8. A drop-out fuse construction comprising an insulator forming a body portion, said body portion being adapted to receive conductors and to be supported therefrom, terminal members carried by said body portion and electrically connected to the conductors, and a drop-out fuse assembly including an insulating fuse tube and a fuse link within said fuse tube, said assembly having contacts at opposite ends thereof normally electrically connected to the .terminal members, one of said contacts being movable away from the corresponding terminal member and the other of said contacts including toggle link mechanism normally held against releasing motion by said fuse link, whereby when said fuse link is ruptured, said toggle link mechanism is released and the contact at the opposite end of said assembly moves away from the corresponding terminal member, said toggle link mechanism pivotally supporting said assembly on one side of said fuse tube and pivotally connected to said fuse tube on the same side of said fuse tube and having a fuse link receiving member on the side of said fuse tube opposite the pivot of said toggle link mechanism, said fuse link receiving member upon rupture of said fuse link moving outwardly away from the corresponding end of said assembly.

9. A drop-out fuse construction comprising an insulator forming a body portion and being of elongated construction and being provided with ends having fiat surfaces, terminal members secured to the ends of said body portion and bearing'against the flat surfaces of said body porlink therein, releasable mechanism pivotally car'- ried by said pivot support and restrained against releasing motion by said fuse link, one portion of said releasable mechanism against one end of said fuse and of said fuse asembly spring latch, whereby when said fuse link is ruptured, said releasable mechanism will cause the opposite end of said fuse assembly tov be released from said spring latch, said fuse assembly thereafter dropping to inoperative position.

WILLIAM o. SCHULTZ.

assembly, the other being held by said normally bearing 

